Method of texturing yarns



United Y @talented Feb.. 27s lh@ Ellanl F. Eitzgerald, Decatur, ein.9 assigner to The strand orp'oraldon, Decatur, Alle, et corpernhon Delaware Filed Sept. d, 2.958, der9 No. 755332 lhis invention relates to a method for texturing yarns and more particularly, to a method for lecturing yarns acrylonitrile polymer filaments.-

Yarns or" iilaments produced from largely acrylonitrile polymers, suchfas those polymers, copolymers, and blends of polymers and copolymers containing at least 70 percent of acrylonitrile by weight in polymerized form, possess a series of properties which render them peculiarly adapted to texturing operations. The polymers from which such yarns arevproduced become plastic and ductile when heated such that-they will assume more or less permanent form `in response to various deformations induced while heated, such-as twisting. `in addition, such yarns possess the further property of stretching when eated under tension to a metastable, or ldimensionally unstable, form subject toV high longitudinal shrinkage. The dimentisional instability can be reduced to a normally stable state 'oy heating and shrinking the yarns. This series of properties combine to enable the production of' textured yarns of peculiarly excellent properties. Yarns can be produced lwith greater compactness, bulk, and covering power than have been produced by other textun'ng processes applied to other natural and synthetic filaments and bers. Such yarns can' be produced with less physical damage to the filaments, such as in their tensile strength and elongation, principally because oi' the absence of severe mechanical action directly on the ilarnent.

Frevious methods ot' teaturlng other synthetic yarns ihave depended on vdeformation of laments in the yarns by means of drawing over a sharp blade, crimping by stuffing into confined heated or unheated vessels, and highly twisting while heating and then untwisting, all of which procedures have resulted in various degrees of more or less permanent crimp imparted to the yarns so treated. Other methods of producing textured yarns have included those which are directed toward increasing the bulk or voluminosty of yarns to approach or surpass that of spun yarns but have involved no self-crimping of the yarns. Such procedures have included entangling filaments bylj'ets of air or gases and bulking acrylic yarns by stretching acrylonitrile polymer filaments under heat prior to breaking or cutting into libers and subsequently relaxing the fibers when the yarns have been blended or plied with already relaxed or untreated dimensionally stable yarns. None of these prior methods have resulted in yarns of acrylonitrile lilaments possessing increased bulk and voluminositr, good um'formity, and greater covering power and at the same time greater compactness and the lelasticity associated with the socalled stretch yarns.

The principal object of the present invention is to provide a method for producing textured acrylonitrile polymer yarns having greatly increased voluminosity. lbulk, covering power and compactness as well as elasticity. A. further object is the provision of a method for producing such acrylonitrile polymer yarns in sizes appropriate for woven and tufted carpets. Other objects will appear from the detailed description hereinafter.

lt has been found that the objects of the instant invention can be accomplished by a method of texturing acrylonitrilc polymer tiliment yarns which comprises continually drawing an acrylonitrile polymer filament yarn from a source of supply, stretching the yarn while heated to a temperature above the second order transition point of 'the acrylonitrile polymer to produce a dimensionally urestable yarn, and concurrently inserting twist in thc yarn,

cooling the yarn to set the latent twist, nntwisting the yarn, and thereafter heating the stretched and twist-set yarn to relax, longitudinally shrink, and develop crimp therein, and thus produce a dimensionally stable yarn having increased uniformity ,'ouminositI compactncss and elasticity.

'Yarns produced by the method of the instant invention can he processed through all the steps outlined above and used in their iinished form for weaving, knitting or tufting into fabrics. Alternatively, the dimensionally unstable yarn with neat set latent twist may be packaged and stored iorsubsequent use before conducting the relaxation, shrinking, and crimp development operation. The yarn in the latter condition can be plied with other similarly treated yarns betore relaxation, shrinking and crimp development to afford similar desirable qualities in the plied yarn. Further. the dimensionally unstable yarn prior to relaxation, shrinking and crimp development can be woven, knitted or tufted into fabrics and thereafter relaxed by suitably heating tbe fabric. Such relaxation in fabric form has been found to be particularly desirable in certain construction of knitted goods and carpets.

The yarns produced by the method outlined above possess greater compactness and covering power than any of the'prior textured yarns, as well as good elasticity. These properties of compactness and high covering power make the yarns produced by the method of the instant invention peculiarly adapted for use in woven and tufted carpets as well as knitted pile fabrics and high voluminosty woven fabrics.

The method of the instant invention is more specitically described with reference to the attached drawing wherein:

FIGURE l is a diagrammatic view of the method of the invention, in which various Well-known forms o apparatus are generally indicated; and

FIGURE 2 is a diagrammatic side elevation of one form oi apparatus for conducting the relaxation step of the instant method.

With reference to FlGURE l, yarn or tow 2 of oriented acrylonitrile filaments is drawn from a source of supply il by feed rolls d and forwarded by the feed or stretching rolls 7, which are driven at a higher peripheral speed than feed rolls 4. Intermediate the feed rolls 4 and stretching rolls 'i the yarn or tow 2 is passed through n heating means and false twist spindle 6. From stretching rolls the yarn or tow 2 is fed to take-up rolls il through heated relaxation means 8 and forwarded by the take-up rolls 9 to package winding means ld.

' The source of the yarn or tow of oriented acrylonitrile polymer filaments may be any suitable yarn package such as a bobbin, pirn, or cone, such as illustrated in FIGURE l, or, in the case of tow the source can be the spinning line 'where such tow is produced directly or cans or boxes of tow obtained from such production line. The feed rolls l are controlled variable speed driven rolls of any desired design while the stretching rolls 7 are likewise controlled variable speed rolls adapted to apply tension to and prevent slippage of the yarn 2. The stretching rolls may comprise nip rolls, godets', or the like. The yarn or tow 2' is passed through the heating means S wherein it is heated and while heated it is twisted through the action of false twist spindle 6 and stretched by stretching rolls 7. The ratio of the peripheral speed of the stretching rolls 7 to the feed rolls l is referred to as stretch ratio. in the instant method the stretch ratio can be varied from approximately l.l to 3.0 or more, but for best results it is generally preferred that the stretch ratio be between 1.2 and 1.8.

matically in FIGURE l, the yarn is relaxed a continuous traveling yarn. Again with reference to PlGURE. l, the yarn or tow 2 is fed into heated relaxation means ti by means of stretching rolls J' and forwarded to package winding means l by the take-up rolls s. ".'tlie heated relaxation means may taire any or" several .-rms, suoi a steam table, steam trough, water bath or the liite. wise, dry heat from a polished surface or a heated continuous oven is satisfactory, so long as good heat distribution to all the larnents is maintained in any l'orrn of the heated relaxation means employing or dry heat a temperature of about 200 F. is for a time sumcient to relax the yarn. When a heated aqueous bath is used a temperature of at least 160 i?. is generally4 isiactory. The yarn Z must be under no tension and ccmpletely free to relax while heated. rlhe yarn must confined by contact with walls or other surfaces and must not be stuffed tightly in any form of heated relaxing means since any unrelaxed and still strained portions will render the yarn unsatisfactory.

T he package-winding means lill may take the form a conc-Winder which produces cones o the Finished relaxed and dmensionally stable yarn a. From such cones the yarn may be transferred to any desired size and type of bobbin, pirn or beam for storage and shipment in conventional manner. Alternatively, the nal packaging may take place directly from the taire-up rolls 9 by employing other well-known package winding means il@ in place of a cone-Winder.

`In another form of the instantl method the or tow which emerges from the stretching rolls 'l can be relaxed in skein form, not shown, by heating with steam or by means of dry heat in a chamber maintained at least at about 200 E., or in an aqueous bath maintained at least at, 160" Preferably, a chamber using live steam at about 260 F. is used. However, dry heat at 200 in an even and an aqueous bath at lotta E. have proved satisfactory.l When relaxed in the iorrn of skeins the relaxed and dimensionally stable yarn thereafter is rev/sund on some form of yarn package prior to use in textife opere-- tions Such rewinding operations are not iliuslzrated in the drawing since any or' the wcll-lrnown commercially practical methods may be employed.

FlGURE 2 illustrates one preferred form of apparatus for conducting the relaxation step of the instant method, With reference to FIGURE 2, dimensionally unstable yarn or tow 2, having latent twist set therein, which emerges from stretching rolls 7 is conducted over guide roller ill, or any other knownyarn-guiding means, and into a wigwag piddler 12. The yarn or tow 2 is forwarded by the piddler l2 onto conveyor belt i3 and carried thereby through a heated relaxing zone i4 to which heat is supplied by a bank of infra-red heat lamps i5. From the conveyer belt 13 the yarn or tow is drawn off by taire-up rolls 16 and forwarded to package winding means li, correspondingrespectively to taire-up rolls El and package winding means l0 in FlGURE l. The wig-Wag pidcller 12 distributes the yarn 2 back and forth onto conveyer belt 13. This form of distribution on the conveyor belt leaves the yarn totally free to relax. in place of infrared heat lamps l the heat for the heated relaxing zone 14 may be derived from a steam chamber or dry heat oven. rrespective'of the heating means used, suriicient heat must be transrnited to all the filaments in the yarn to substantially completely relax and shink the yarn and to develop the crimp therein.

Another aspect of the instant method is the fact that the dimensionally unstable yarn having latent twist set therein, which emerges from thestretching rolls, can be relaxed and the crimp developed after the yarn has been woven, knitted or tufted` into fabrics. When conducting the method in the latter manner, the yarn or tow from the stretching rolls, with no further processing, can be wound upon rigid cones by means of a constant tension conewlnder and may be stored for extended periods in this marmer without damage or loss of dimensional instability due to relaxation. Relaxation subsequent to weaving, lnn'tting, or turting can be achieved by subjecting the resulting fabrics to heat in the same manner as the yarn is relaxed. Thus, the fabric can be heated by steam or dry heat in a chamber maintained at least at about 200 l?, rrlternarively, the fabric may be heated in an aqueous medium maintained at least at about 160 l?. Suitably this heating in an aqueous medium may be carried out in separate operation, or preferably, in conjunction with yeing, scouring, nishing, etc. of textile fabrics. Relaxaon can also talee place after any subsequent processing steps through which the yarn is put, such as plying, where the unrclaxed yarn is plied with other yarns before relaxation. dehnt ion in a cut-pile tufted carpet has been found to consist in first plying two or more ends of unrelarted yarn and then relaxing said yarn and developing the crimp before tuiting a carpet fabric therefrom.

The alternative method shown by the broken line of llGURil illustrates the application of the principles discussed above. With reference to the broken line of FIG- URE l, the dimensionally unstable yarn or tow 2 having latent twist set therein from stretchin;J rolls '7 is processed through the desired fabrication operation i3 of knitting, weaving, or tuitirig and the yarn in the resulting fabric i9 thereafter relaxed by means of heat. The heating as apiied in heating zone 20, may occur in a separate operation or in the subsequent operations of scouring, dyeing, finishing, etc. The relaxed fabric i9 is forwarded by conventional rolls El to conventional fabric take-up means 22 from which the fabric may be suitably packaged for storage or shipment. Wet heat of at least 160 F. or dry heat of at least 200 F. is suliicient to relax the yarn in the form or knitted, woven or tufted fabric. Since ternperatures of at least lo0 F, are customarily maintained in aqueous baths during the operations of scouring, dyeing, finishing, etc. this alternative means of relaxation is conveulent. Upon relaxation in the form of fabric, the previously unrelaxed yarns in the fabric will have been shrunlt and rendered dirnensionally stable and the latent twist set therein will have been developed as crimp in the yarns.

The method of the instant invention pertains to all continuous multiiilament yarns, tows, etc. and to plied yarns resulting from plying two or more ends of such continuous tilarnent yarns composed of predominantly acrylonitrile polymers. it is applicable to all acrylonitrile polymer yarns of filaments produced from polymers, including copolymers and interpolymers, containing or more percent by weight of acrylonitrile in polymerized form and bler-ds of such polymers with blending polymers, which preferably contain acrylonitrile. The copolymers and interpolymers can be polymers of 70 or more percent of acrylonitrile and minor proportions of other mono-Oleiinic monomers copolymerizablc therewith. Among the mono-olefinic monomers useful for copolyrncrization with acrylonitrile are vinyl acetate and other vinyl esters of monocarboxylic acids having up to four carbon atoms, methyl acrylate and other alkyl acrylates having up to four carbon atoms in the alkyl radical, methyl methacrylate and other alkyl methacrylatcs having up to four carbon atoms in the alkyl radical, acrylic, alpha-chloroacrylic, and mcthacrylic acids, vinyl chloroacetate and other vinyl esters of halogen-substituted monocarboxylic acids, dialkyi fumarates, maleatcs, and crotonates having up to four carbon atoms in the alkyl radicals, styrene, alpha-methylstyrene, and other vinyl or allrenyl-substituted aromatic hydrocarbons, vinyl chloride, vinylidene chloride, and other vinyl and vinylidene halidcs, methacrylonitrile, methyl vinyl ketone, N-vinylcaroazole, vinyl urane, and vinyl or alkenyl-substiuted N-heterocyclic tertiary amines, such as the vinylpyridines and alkyl-substituted vinylpyridirles, vinylimidazolc and alkylsubstituted vinylinridazoles, vinylquinolines and alkyl- Thus, one method for obtaining good tuft' substituted vinyloninolines, 'v' i f 1- :ratori is uniform ne he propstituted vinylpyrazines, vinyl i onya is. Mechanical process azoles. The blended compositto i i t i reciente! ali unevenness and irregu of the above copolymers f proportions or one or more bl uf at least 30 percent of e. reed'1 such as 'the vinyl or atertiary amines above 'e mono-oienie monomer Among the mono-oieiiuie mono m 'zaton with the 'ving/ or elke amines to forro the bien" mehylstyrene, vinyl naphhereoe wl ting employed, but since i the yarn in stretched forro, any J resulting therefrom are greatly n. The yarns produced by the vantagcous properties of ref', oornpactness und streichrEhe chief source of irreguidene chloride, y yl rice f acryiouitrile, memacrylonitriie. i. j, ffrdely different embodiments o; acids7 the alkyl ecrylates ai f "i rade 'without departing from the tomates, alkyl fumarates, eik; `r it is to be understood that the Acrvlonirile is the nrerered 5^" fil@ SPCCC @mbodmcls polymers because t-e i. r f except as defined in the zo vent resistance of .such

There are ser out bei typesl of textured yarn method of the instant in factory carpet yarn for there was used n continuous composed of a blend o rner of 94 percent acryl' tate by weight and l2 per cent acryloniti and SO by weight. The coniinuous posed of '150 laments of 2250. lThis tow was he tube for a residence time o employing set` rn thus beate-d ratio of 1.5 a t inch by a false t stable yarn was therein by heating in s live steam at 260 uum for one minute, s vacuum for one minute to :MM e sulting yarn was Found e 60 to 65 percent from its very uniform and bulky and .i elastic with crimp well develope method oi' exturing ecrylonltrile polymer carpet Ari continually drawing a continuous ryiori rile polymer tow of at least 750 .e -icrylonitrile polymer to produce a dimento, concurrently inserting twist in the ner veine of from 8 to l5 to form .e yarn oelow the second order transition he t inserted therein, untwisting thereafter heating the he twist, ano

. y there is produced a dimensionaltl ele-.Stic carpet yarn. etl'iod ci? tof-:turion ecrylonirile polymer carpet .ses c innally drawing a continuous polymer low of et least 750 letal c'Y er Li n source of supply, stretching the tow a stretch rullo from about l.l to 3.0 while heated to a te'nrerature above second order transition iernperature of the acrvionitrile polymer to produce a dimensionaiiy unm stable tow, concurrently inserting,7 twisi in the tow ut a found to demonstrate Supefigf iwi multiple; value of from 8 to l5 to form a yarn, coolpowe, and freedom from 5;; i ynribelow the second order transition tenu tufgd-thgyefmd, perature to set the twist inserted therein untwisting the A smaller Engel- Cm-peg m fr@ md5 i yarn to remove the twist, thereafter fabricating the yarn of filaments of the Same bien@ rio carpetfabrio and subjecting the resulting fabric as above wherein the tow was eornoo :he stretched and twist-set yarn to heut at a Vof ljdeniefg a 'total 10W Egg-Sge; i 75 ten Woratore selected from the group consistinn of at least r .e heated on a gmgved hearing b t ot" wet and at least 200 te. dry for a time sufficient dem@ ime gf approximate@ shrink and `eyelop crimp in the yarn, whereby to a 1.11 stretch ratio and a twist of a false twist spindle. rille dimeosi was then relaxed and the cr n in a chamber supplied wih satt pressure for about l5 secon I. Y produced by increasing the residence time or block to about 3 seconus. The resulting yu 1^ i to have contracted approximately' `f unrelaxed lengths. These yarns oeinorrsmal o pro? stretchlness and bull(- as well es good compos* covering power. These properties indicate 5uc 1 be suitable for knit goods and e rpes,

.From the foregoing it may oe :een i` the instant invention is 7eroe" plieL wide range of extremely useful ie". nitrile iliamente. The method rest ity in the yarns produced. suine the yarns to uniform conditions of tern sion while stretching and twis there is produced a carpet fabric containing a dimensionally stable, crimp-ed and elastic yarn.

irl

e method donned in claim wherein the yarn ated into a knitted fabric.

outhori as defined in claim 2 wherein the yarn Cit.

as defined in claim 2 wherein the yarn tufted fabric, 

1. A METHOD OF TEXTURING ACRYLONITRILE POLYMER CARPET YARNS WHICH COMPRISES CONTINUALLY DRAWING A CONTINUOUS MULTIFILAMENT ACRYLONITRILE POLYMER TOW OF AT LEAST 750 TOTAL DENIER FROM A SOURCE OF SUPPLY, STRETCHING THE TOW AT A STRETCH RATIO OF FROM 1.1 TO 3.0 WHILE HEATED TO A TEMPERATURE ABOVE THE SECOND ORDER TRANSITION TEMPERATURE OF THE ACRYLONITRILE POLYMER TO PRODUCE A DIMENSIONALLY UNSTABLE TOW, CONCURRENTLY INSERTING TWIST IN THE TOW AT A TWIST MULTIPLIER VALUE OF FROM 8 TO 15 TO FORM A YARN, COOLING THE YARN BELOW THE SECOND ORDER TRANSITION TEMPERATURE TO SET THE TWIST INSERTED THEREIN, UNTWISTING 